1. Field of Invention
This invention relates generally to the art of forming radius bends in pipe, conduit, tubing and the like. Particularly, this invention relates to a mobile carriage structure which may be used for mounting various makes and models of commercially available "three point" type pipe and conduit bending frame assemblies, in a stationary, upright, operating position. The mobile carriage structure has provision for storing different sized bending shoes and other accessories as well as for mounting a power source, such as a hydraulic pump and electric motor, for operating the hydraulic ram of the bending frame assembly. This invention also relates to a detachable leveling clamp for use in bending nonferrous metallic pipe or conduit with the bending frame assembly. This disclosure also relates to a method for producing single radius bends, or a series of spaced or offset radius bends ("following" bends), in nonferrous metallic pipe or conduit using a conventional "three-point" type bending frame assembly mounted in a stationary, vertical, operating position on the mobile carriage structure of the present invention and using the detachable leveling clamp of the present invention.
2. Description of Prior Art
Heretofore, in the pipe and conduit bending art, various arrangements for mounting "three point" type bending frame assemblies in an upright operating position have been provided. As exemplified by U.S. Pat. No. 3,396,565, previous mobile mounting arrangements have comprised a relatively long base, supported on wheels, pivotally mounting a bending frame assembly thereon. Also, such earlier devices were provided with clamping means for holding the length of pipe or conduit, in which a bend is to be formed, rigidly to the base during bending. During the bending operation, the bending frame assembly itself is caused to pivot about its mounting on the base, as the bend is formed, as shown in U.S. Pat. No. 3,760,626. Another earlier device provided a pivotal mounting for both the bending frame assembly and the supporting means holding the pipe or conduit, as disclosed in U.S. Pat. No. 3,981,173.
Still another earlier arrangement, known to these inventors, for mounting a tubing bender, is exemplified by U.S. Pat. No. 3,935,721, which discloses a "swinging-cam" type tubing bender disposed in a horizontal operating position on a framework mounted on casters for mobility. Other horizontally operated benders, known to these inventors, are shown in U.S. Pat. Nos. 3,844,158 and 3,918,286. The pipe-bending apparatus of U.S. Pat. No. 4,265,106 discloses a horizontally operated bender mounted on a sawhorse type frame upon which are mounted a hydraulic pump and electric motor as well as a means for storing forming heads (bending shoes) for bending pipe, when not in use.
Various makes and models of "three-point" bending frame assemblies are available commercially. These assemblies are typically used in a horizontal operating position, either on a floor at the job site, or upon a bench or platform in the shop of the contractor. A separate hydraulic pump is typically connected by a hose to the hydraulic ram of the bending frame assembly for actuating the hydraulic ram. When the bending operations have been completed at one location, the bending frame assembly, hydraulic pump, and various bending shoes are typically dismantled and packed into a large case or locker and transported therein to the next location where bending operations are to be performed. At the new job site the bending frame assembly, the hydraulic pump and the bending shoes must be unpacked and the hose from the hydraulic pump reconnected to the hydraulic ram, before further bending operations may proceed.
As long as the pipe or conduit being bent is of relatively small diameter, the bending frame assembly, hydraulic pump and bending shoes will typically be relatively small in size. Being thus lighter in weight, their transportation from location to location will not be overly difficult. One man can accomplish the move, although not always easily. However, when pipe or conduit of larger diameters are to be bent, the weight and size of the bending frame assembly alone may often require two or more men to transport the bender and set it up. Also, the hydraulic pump necessarily will be heavier and more bulky as will the electric motor which powers the pump. Where pipe or conduit of different diameters is to be bent at a variety of locations, various bending shoes will necessarily have to be transported as well from location to location. On large jobs, such as in the construction of multi-story buildings, where pipe and conduit bending operations must be performed in many locations, it becomes apparent that much time and effort will necessarily be expended just in transporting a bending frame assembly and its associated motorized hydraulic pump and various bending shoes from location to location. When the time and effort necessarily expended in just dismantling, packing, unpacking and setting up the bender at each location is added to the time and effort required for its transportation, it becomes more apparent that the use of the various commercially available bending frame assemblies entails the drawback of significant time and effort expended in performing these basically non-productive operations.
A further non-productive expenditure of time and effort will necessarily occur daily when the case or locker, in which the bending frame assembly, hydraulic pump and bending shoes are packed, must be transported to and from the secured overnight tool storage area, typically provided at construction sites, to and from the location where bending operations are to be performed during the workday. Loading the case or locker onto a wheeled cart for transporting, or mounting wheels or casters to the case or locker itself, facilitates transportation of the bender but still does not alleviate the amount of time and effort required to set up, dismantle, pack and unpack, the components of the bender themselves.
Another shortcoming, which becomes apparent as the bending frame assembly is typically positioned on the floor of the job site in a horizontal operating position, is that bending operations, especially when bends are to be performed in long lengths of pipe or conduit, require considerable unobstructed floor space to allow clearance for the ends of the pipe or conduit to swing as the bend is being formed. Associated with this space requirement is the difficulty of accurately gauging the desired degree of bend when the ends of the pipe or conduit, in which the bend is being formed, are swept across a horizontal plane.
Apparatus for mounting a bending frame assembly in a vertical operating position partially overcomes the disadvantages described above of horizontal operation. However, prior art apparatus, as exemplified by U.S. Pat. Nos. 3,396,565, 3,760,626 and 3,981,173 are large in overall size in comparison to the actual bending frame assemblies mounted therein. Because of this large overall size, such prior art apparatus are more suited to shop use rather than use on location at the job site. Although the apparatus of U.S. Pat. Nos. 3,396,565 and 3,981,173 may be provided with supporting wheels for mobility, the size and weight of the apparatus requires at least two men for moving them from location to location. Also, as the overall length of these benders may exceed the interior of service elevators, these prior art apparatus cannot always be moved directly to the job site.
As can be concluded from the above observations, it is desirable to provide a compact, mobile apparatus, for mounting a bending frame assembly in a vertical operating position, which apparatus is easily transportable by one man and is simple in operation. Also the apparatus must have provisions for mounting a hydraulic power source, bending shoes of various sizes and accessories used in performing bending operations on pipe, conduit, tubing and the like.
Mounting the bending frame assembly in a vertical operating position offers obvious advantages in that the length of pipe, conduit or the like, in which bends are to be formed, will move only in a vertical plane rather than in a horizontal direction, that is, in a parallel plane relative to the vertical axis of excursion of the hydraulic ram of the bender. Also in a perpendicular plane relative to the horizontal plane of the floor or ground at the job site.
This vertical plane of movement (of the pipe, conduit, tubing and the like, in which bends are to be formed) permits gauging of the bend being formed by the use of an inclinometer and/or spirit level gauging instruments positioned upon the length of pipe, conduit, or the like, being bent. A device of the inclinometer type is illustrated in U.S. Pat. No. 3,396,565 and comprises an indexed circular dial with a swinging pendulum indicator arm. The device is frictionally attachable to a length of conduit by means of a releasable clamp chain to indicate degree of bend by the angular displacement of its indicator arm relative to its indexed circular dial. A number of other depth-or-degree of bend indicating means are discussed in U.S. Pat. No. 3,935,721.
Typically in gauging bends formed on vertically operating bending frame assemblies, an inclinometer and/or spirit level gauging instrument is attached by frictional clamping or magnetic means, along one or both ends of the length of pipe, conduit or tubing being bent. This procedure permits measuring of the angular displacement of the ends about the radius of the bend as it is being formed.
Often it is necessary to form two or more bends of different radii in a length of pipe, conduit or tubing. These bends may typically lie in the same vertical plane while having their radial bend centerpoints displaced or offset axially along the length of pipe ("following" bends), conduit or tubing. Typically, such compound or offset bends will have their radial bend centerpoints displaced above and below the length of pipe, conduit or tubing, as well, e.g. where "S" bends are being formed. In such cases it is often difficult, when using the bending apparatus and gauging instruments of the prior art, to assure that these offset bends are formed in the same plane with respect to one another. The clinometer device shown in U.S. Pat. No. 3,396,565, for example, while rigidly clampable to the tubing being bent, and therefore usable in an inverted position, such as when the tubing is rotated 180 degrees in the bending frame assembly, for forming an "S" bend, has inherent disadvantages in that, when used with the bending apparatus therein disclosed, there may not be sufficient clearance provided below the tubing to permit such inverted use of the clinometer. Even where sufficient clearance permits such inverted use, the dial index markings will face in the opposite direction, i.e. rearward, thus forcing the operator to peer around the other side of the apparatus in order to view the angular displacement of the indicator arm, making the bending operation awkward to control. Where clearances will not permit such gauging in inverted use and where bends in perpendicular planes are to be formed in the same length of tubing, the clamping means must be loosened and the gauging device rotated 180 or 90 degrees about the tubing. This reorientation must be precisely formed, to assure accurate alignment of the finished bends in relation to one another.
A common method for gauging bends being formed with vertically positioned bending frame assemblies, and one preferred by these inventors, involves the use of a type of inclinometer device known as a protractor level. This type of device combines an indexed protractor dial, similar to the indexed dial shown in U.S. Pat. No. 3,396,565, a spirit level, and a base portion which is pivoted about the centerpoint of the protractor dial. The protractor dial is provided with markings in an arc about its peripheral face indicating degrees of angular displacement about its center. The spirit level vial is mounted to the protractor dial in such manner as to align the axis of the level, (i.e. the longitudinal axis perpendicular to plumb and usually indicated by the bubble at rest, centered in the vial) in parallel relationship to the baseline of the protractor level (i.e., the axis describing an angular displacement of 180 degrees about the centerpoint and usually indicated as 90 degrees displaced about a "zero" or plumb line). The pivoted base portion is provided with a flat bottom surface which may also have a "V" grooved edge for placement upon a curved surface such as pipe or conduit. The bottom of the base portion may also be magnetized for attachment to ferrous metal surfaces. The upper edges of the base portion are provided with index markings aligned 180 degrees about the pivot center so that when the protractor level is placed upon a level surface the protractor baseline is aligned with the index markings of the base portion and the bubble is centered in the vial of the spirit level.
The dial of the protractor level is typically marked in major increments of fifteen degrees and multiples thereof. In this way, typical bends in lengths of pipe, conduit or tubing, from 15 degrees to 90 degrees, may be gauged by simply aligning the base portion index lines with the incremented degree markings on the protractor dial corresponding to the desired degree of bend. Once the desired degree of bend has been dialed in, the protractor level is placed upon the top surface of the length of pipe or conduit being bent. Then the bend is formed until the bubble in the spirit level vial is centered in the "level" position, at which point the desired degree of bend dialed in has been reached.
Where compound, offset or "S" bends are to be formed ("following" bends), and where the conduit being bent is of nonferrous metal, it is still difficult to assure accurate alignment of bends when using a protractor level. This difficulty arises because the conduit in these situations must be rotated and conventional protractor levels are suited only for placement atop the conduit. Even when provided with a "v" grooved, magnetized base, the protractor level must be accurately reoriented atop the rotated conduit before forming can be continued.
Thus, it is desirable to provide a means by which accurate alignment of compound bends in the same plane may be easily and consistently accomplished on verticlly mounted bending frame assemblies, yet permit the use of conventional protractor level gauging instruments for monitoring the degree of each bend formed.
Prior art known to these inventors includes the following U.S. Pat. Nos.:
______________________________________ 2,621,702 12/1952 Peddinghaus et al 3,396,565 8/1968 Miller 3,760,626 9/1973 Sharar 3,844,158 10/1974 Mercer 3,918,286 11/1975 Whitehead 3,935,721 2/1976 Boteler et al 3,949,584 4/1976 Pearson et al 3,981,173 9/1976 Nobinger 4,265,106 5/1981 McMaster et al ______________________________________